JPH0431809B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a method for automatically tightening threaded parts such as cross-recessed screws, hexagonal socket screws, or bolts, in which the driver bit returns after screw tightening is completed. The present invention relates to an automatic screw tightening machine configured to smoothly release the engagement between a driver bit and a screw head.

[Conventional technology]

Generally, automatic screw tightening machines are configured to transmit the rotation of a rotary drive source to the driver bit through a built-in torque clutch mechanism, and as the rotary drive source descends, the screw at the tip of the driver bit tightens. comes into contact with the workpiece and the screw begins to be screwed into the workpiece, and then, when the screw has finished being screwed into the workpiece, a torque clutch mechanism is activated to interrupt the rotation of the driver bit.

[Problem that the invention seeks to solve]

When tightening a screw into a specified position using this type of automatic screw tightening machine, there is no problem until the screw is tightened by the driver bit, but after tightening is completed, when the driver bit returns to its original position, the head of the screw The head hole of the screw may be damaged due to the tight engagement between the hole and the tip of the driver bit, and sometimes the entire workpiece may be pulled up, which not only damages the workpiece, but also damages the tip of the driver bit. Problems such as these are occurring.
Such problems are particularly noticeable when tightening hexagon socket head screws, bolts, and nuts.

[Means for solving problems]

The present invention has been made with the aim of solving the above-mentioned problem, and a rotary drive source 6 having a built-in torque clutch mechanism is fixed to a driver body 21 which is movable by an elevating source 2, and the driver body 21 is
In an automatic screw tightening machine configured to transmit the rotation of the drive source to a freely rotatable driver bit 18 in a chuck unit 26 disposed in front of the screwdriver, a mesh drive clutch 8 is connected to a drive shaft 7 of a rotary drive source 6. In front of this meshing drive clutch 8, there is disposed a meshing driven clutch 9 which can freely mesh with the meshing drive clutch 8 and can be moved back and forth by a forced operation means fixed to the mounting member 5 that fixes the driver main body 21. , a fixing member having a meshing surface 10b opposite to a meshing surface 10a formed on the driver body 21 which rotatably and reciprocally supports the meshing driven clutch 9 in front of the meshing driven clutch 9. Install 11,
Further, a driven shaft 15 having a guide tube 16 having a cam groove 17 is connected to the meshing driven clutch 9, and both ends of the guide tube 16 are locked in the cam grooves 17 and rotated together with the driven shaft 15. A locking pin 20 is embedded in the driver bit 18 so as to do so.

[Effect]

The rotational drive source 6 operates, and the meshing drive clutch 8
The driver main body 21 moves forward while rotating. As a result, the driver bit 18 and the guide sleeve 23 which rotatably houses the driver bit and holds the screw 22 are further lowered. Subsequently, the guide sleeve 23 stops just before coming into contact with the workpiece 33, and the screw 22 is pressed against the workpiece 33 by the driver bit 18. Therefore, the driver body 21 and the driver bit 18 move relative to each other, and this movement causes the driven clutch 9 to engage with the forced operation means as a locking means for the driven clutch 9.
The dog-driven clutch 9, whose pressing operation has been released, moves back and meshes with the dog-drive clutch 8. Then, the driver bit 18 rotates and the screw 22 is screwed into the workpiece 33.

In this way, when the screw 22 is tightened to a predetermined tightening torque, the driver main body 21 rises and the forced operation means operates, and the meshing driven clutch 9 is pressed against the fixing member 11. is fixed to the driver body 21. After this, when the driver main body 21 continues to rise, the locking pin 20 of the driver bit 18 moves along the cam groove 17 of the guide tube 16, so the driver bit 18 adjusts the inclination angle of the cam groove 17 in the direction of loosening the screw 22. only reversed. As a result, the driver bit 18 and the head hole of the screw 22 are disengaged, the driver body 21 is moved back to its original position, and the screw tightening operation is completed.

〔Example〕

Examples will be described below based on the drawings. In FIG. 8, reference numeral 1 denotes an automatic screw tightening machine, which has a bracket 3 for fixing a lifting source 2. As shown in FIG. A guide shaft 4 is fixed to this bracket 3. A mounting member 5 is slidably guided on the guide shaft 4, and is configured to be raised and lowered along the guide shaft 4 by the lifting source 2. A rotary drive source 6 having a built-in torque clutch mechanism (not shown) is fixed to the upper part of the mounting member 5. As shown in FIG. 1, a meshing drive clutch 8 having meshing teeth at its tip is connected to the drive shaft 7 of the rotational drive source 6, and the meshing drive clutch 8 is located on the same center line as the A meshing driven clutch 9 is arranged which has teeth that can mesh with the teeth. The mesh driven clutch 9 has a guide shaft portion 9a loosely inserted into the guide hole 8a of the mesh drive clutch 8 while being elastically biased. Further, a meshing surface 10a having a serrated or knurled cross-section in the circumferential direction is formed on the front surface of the outer periphery of the meshing driven clutch 9. The meshing surface 1 of the meshing driven clutch 9 of the fixed member 11 fixed to the mounting member 5
It can be engaged with the other engagement surface 10b formed at a position opposite to 0a. Also,
As shown in FIG. 2, the tip of a lever 12 is slidably disposed on the rear surface of the outer periphery of the meshing driven clutch 9, and the lever 12 swings on a support pin 13 whose both ends are supported by the mounting member 5. It is pivoted for free movement. A piton rod 14a of a piston cylinder 14, which is fixed to the mounting member 5 and serves as a forced operation means, is connected to the other end of the lever 12.
The piston cylinder 14 is set to move downward when the elevating source 2 is moving downward, and to move upward when the elevating source 2 is moving upward.

On the other hand, as shown in FIG. 1, a driven shaft 15 is connected to the dog driven clutch 9, and a guide tube 16 is formed on the driven shaft 15. A cam groove 17 is cut into this guide cylinder 16, which rotates the driver bit 18 in the direction of loosening when a locking pin 20 (to be described later) descends relative to this guide cylinder 16, that is, relative to the axis. A cam groove 17 is cut that slopes in the direction of screw tightening rotation as it reaches the top, and the locking pin 2 implanted in the driver bit 18 is inserted into this cam groove 17.
0 stands out and the driver bit 1
8 is configured to be elastically biased downward by a spring 19 disposed around the guide tube 16.
Further, a driver main body 21 with the fixing member 11 fixed to the upper part is arranged on the outer periphery of the guide cylinder 16, and a holding cylinder 24 with a guide sleeve 23 attached to the tip that holds the screw 22 by suction is attached to the outer periphery of the driver body 21, which can be moved up and down. The holding cylinder 24 is freely inserted and is prevented from coming off by a locking member 25. This holding cylinder 24 is configured so as to come into contact with a stopper 27 implanted in a chuck unit 26, which will be described later, to stop further descent, and to suck the air inside the guide sleeve 23 by a suction mechanism 28.
The guide sleeve 23 is configured to accommodate the tip of the driver bit 18 inside, and the screw 22 located below the guide sleeve 23
It is constructed so that it can be sucked in.

On the other hand, a chuck unit 26 is fixed below the bracket 3. The chuck unit 26 has a chuck body 29, into which the guide sleeve 23 and driver bit 18 can be freely inserted. A pair of chuck pawls 30 are provided on the chuck main body 29 so as to be openable and closable and always resiliently biased in the closing direction. Further, a hose fitting 31 is fixed to the chuck main body 29, and a parts supply device (not shown) is connected to this hose fitting 31 via a feeding pipe 32, and a component supply device (not shown) is connected to the hose fitting 31 through a feeding pipe 32. screw 2
2 is supplied to the chuck pawl 30.

Next, the operation of this embodiment will be explained. When the screw 22 is supplied to the chuck pawl 30 of the chuck unit 26, the elevating source 2 is activated and the driver body 21 is lowered together with the mounting member 5. At this time, the piston cylinder 14 of the forced operation means is activated, the lever 12 is rotated as shown in FIG. 3, and the pressure on the engaged driven clutch 9 is released. At the same time, the rotary drive source 6 rotates, and the meshing drive clutch 8
rotates. In this manner, the driver body 21 is lowered, the screw 22 is attracted into the guide sleeve 23, and the screw 22 is held at the tip of the driver bit 18. Subsequently, the whole unit descends, and when the tip of the screw 22 comes into contact with the workpiece 33, the driver bit 18
Due to the relative movement between the two, the meshing driven clutch 9 is raised, the meshing surfaces 10a and 10b are disengaged, and the meshing drive clutch 8 is engaged with the meshing drive clutch 8, so that the rotation is transmitted to the driver bit 18. At this time, the holding cylinder 24 comes into contact with the stopper 27 on the upper part of the chuck unit 26 and stops at that position.
In this state, when the driver main body 21 descends, a preset thrust is applied to the driver bit 18, and the screw 22 begins to be screwed into a predetermined position on the workpiece 33. At this time, since the descending speed of the driver bit 18 is slower than the descending speed of the driver body 21, the driver bit 18 relatively rises.

In this manner, when the screw 22 is screwed into a predetermined position and with a predetermined torque as shown in FIG. 4, the rotation of the driver bit 18 is stopped. Then, when the lifting source 2 starts the return operation, at the same time, the fifth
As shown in the figure, the piston cylinder 14 also operates,
The lever 12 is rotated and the meshing driven clutch 9 is pushed down so that the meshing surface 1 of the meshing driven clutch 9 is pushed down.
0a and the meshing surface 10b of the fixed member 11 mesh with each other to prevent rotation of the driven clutch 9. If it continues to rise in this state, the locking pin 20 moves along the cam groove 17, the driver bit 18 reverses, and the tip of the driver bit 18 and the screw 22 are no longer engaged. Since the driver main body 21 and the holding cylinder 24 rise in this state, the screw 22 and the workpiece 33 are not damaged at all.

Further, FIGS. 6 and 7 show other embodiments of the present invention in which the shape of the cam groove 17 is changed. This is formed by forming an inclined part 17a in the front of the guide cylinder 16 which is inclined in the direction of screw tightening rotation as it reaches upwards with respect to the axis, and a straight part 17b which is continuous with this and is parallel to the axial direction. This is a cam groove 17 in the shape of a letter, and when the screwing is completed, the locking pin 20 is located in this straight part 17b, so that when the driver bit 18 returns to the upward position, the engaged driven clutch 9 is temporarily held by the piston cylinder 14. Even when pushed downward, the cam groove 17 does not act on the locking pin 20, so no screw tightening force is applied. Further, in this embodiment, the piston cylinder 14 is used as a force operating means for the lever 12, but the piston cylinder 14 may act directly without using the lever 12. Furthermore, instead of these means, for example, a cam may be attached to the motor and the lever 12 may be actuated by this cam.

In this embodiment, the rotation of the meshing driven clutch 9 and the driven shaft 15 is stopped by a forced operation means, but this rotation can be stopped immediately after the screw has been inserted by using an electromagnetic brake, for example. You may also do so.

〔Effect of the invention〕

As explained above, in the present invention, a rotary drive source 6 having a built-in torque clutch mechanism is fixed to a driver main body 21 which is movable by an elevating source 2, and a chuck unit 2 is arranged in front of the driver main body 21.
In an automatic screw tightening machine configured such that the rotation of this drive source is transmitted to a driver bit 18 that is freely rotatable in a rotary drive source 6, a mesh drive clutch 8 is connected to a drive shaft 7 of the rotary drive source 6, and the mesh drive clutch 8 is connected to a drive shaft 7 of the rotation drive source 6. A meshing driven clutch 9 is disposed in front of the meshing driven clutch 8, which can be freely engaged with the clutch and can be moved back and forth by a forced operation means fixed to the mounting member 5 that fixes the driver body 21. A fixing member 11 having a mating surface 10b opposite to a mating surface 10a of the mating driven clutch 9 is attached to the driver body 21 which rotatably and reciprocally supports the clutch 9, in front of the mating driven clutch 9.
Further, a driven shaft 15 having a guide tube 16 having a cam groove 17 is connected to the meshing driven clutch 9, and both ends of the guide tube 16 are locked in the cam grooves 17 and rotated together with the driven shaft 15. A locking pin 20 is embedded in the driver bit 18 so as to do so.

Therefore, it is possible to smoothly release the jamming between the driver bit and the head of the screw that occurs at the same time as the screw is tightened into the specified position by the driver bit, and prevent the driver bit from destroying the head of the screw after the screw has been tightened. Not only will everything disappear,
The raising of the driver bit does not stop due to the action on the workpiece into which the screw is inserted, and the workpiece is not damaged, drastically reducing the occurrence of defective products. Furthermore, even if the workpiece is changed and the tightening height changes, there is no need to adjust the relationship between the locking pin and the cam groove, so there are advantages such as easy maintenance and inspection. Although the embodiments have been described with respect to screws and driver bits, similar effects can be obtained with bolts and box bits.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of the present invention, FIG. 4 is an enlarged perspective view of a main part of the present invention, FIGS. 3 to 5 are explanatory diagrams of the operation of the present invention, and FIGS. FIG. 8 is an overall explanatory diagram of the present invention. 5 is a mounting member, 6 is a rotary drive source, 7 is a drive shaft, 8 is a meshing drive clutch, 9 is a meshing driven clutch, 10a, 10b are meshing surfaces, 11 is a fixed member, 12 is a lever, 14 is a piston Cylinder,
15 is a driven shaft, 16 is a guide cylinder, 17 is a cam groove,
17a is an inclined part, 17b is a straight part, 18 is a driver bit, 19 is a spring, 20 is a locking pin, 21 is a driver body, 22 is a screw, 24 is a holding cylinder, 25
26 is a locking member, 26 is a chuck unit, 27 is a stopper, 29 is a chuck body, 30 is a chuck pawl, and 33 is a workpiece.

Claims (1)

[Claims] 1. Driver main body 21 movable by lifting source 2
This automatic screw tightening machine is configured such that a rotary drive source 6 having a built-in torque clutch mechanism is fixed thereto, and the rotation of this drive source is transmitted to a driver bit 18 which is rotatable within a chuck unit 26 disposed in front of the driver main body 21. A meshing drive clutch 8 is connected to the drive shaft 7 of the rotational drive source 6, and a meshing driven clutch 9 that can be forcibly engaged with the meshing drive clutch 8 is arranged in front of the meshing drive clutch 8. On the other hand, a locking means is attached to the driver main body 21 to fix the meshing driven clutch 9 immediately after the screwing operation is completed;
Further, a meshing driven shaft 15 having a guide cylinder 16 having a cam groove 17 is connected to the meshing driven clutch 9, and both ends are locked in the cam groove 17 of the guide cylinder 16 and are integrated with the driven shaft 15. The locking pin 2 is attached to the driver bit 18 so that it rotates.
An automatic screw tightening machine characterized by having 0 installed. 2. The locking means is formed on a meshing surface 10a formed on the front surface of the meshing driven clutch 9 rotatably and reciprocably supported by the driver body 21, and on a fixing member 11 fixed to the driver body 21, and 2. The automatic screw tightening machine according to claim 1, further comprising a mating surface 10a of the driven clutch 9 and a mating surface 10b opposing the mating surface 10a of the driven clutch 9. 3. Automatic screw tightening according to claim 1 or 2, characterized in that the meshing driven clutch is configured to be moved back and forth by forced operation means fixed to the mounting member 5 that fixes the driver body 21. Machine. 4. The automatic screw tightening machine according to claim 1, 2 or 3, wherein the cam groove is inclined in the direction of screw tightening rotation as it reaches upward with respect to the axis. . 5. A patent characterized in that the lower part of the cam groove is inclined in the direction of screw tightening rotation as it reaches upwards with respect to the axis, and the upper part continuous thereto is dogleg-shaped and is formed parallel to the axis. An automatic screw tightening machine according to claim 1, 2, or 3.